1. Field
At least some example embodiments of the inventive concepts herein relate generally to a semiconductor memory device, and more particularly, to an operation method of a nonvolatile memory device and/or an operation method of a memory controller controlling the nonvolatile memory device.
2. Related Art
A semiconductor memory device is embodied using semiconductor such as silicon Si, germanium Ge, gallium arsenide GaAs, indium phospide InP, etc. A semiconductor memory device is classified into a volatile memory device and a nonvolatile memory device.
A volatile memory device loses its stored data when its power supply is interrupted. Examples of a volatile memory device include a static RAM (SRAM), a dynamic RAM (DRAM), a synchronous DRAM (SDRAM), etc. A nonvolatile memory device retains its stored data even when its power supply is interrupted. Examples of a nonvolatile memory device include a read only memory (ROM), a programmable ROM (PROM), an electrically programmable ROM (EPROM), an electrically erasable programmable ROM (EEPROM), a flash memory device, a phase-change RAM (PRAM), a magnetic RAM (MRAM), a resistive RAM (RRAM), a ferroelectric RAM (FRAM), etc.
As semiconductor integration technology improves, flash memory devices become smaller. Accordingly, a space between word lines may become more narrow. As a result, an incorrect operation may occur due to a coupling between word lines. To overcome these issues, a method is used of reading out a program state of memory cells connected to the selected word line by applying a voltage higher than an unselect read voltage by a predetermined level to word lines adjacent to a selected word line.
However, since a high voltage is applied to an adjacent word line, in the case that a flash memory device repeatedly reads a same page, deterioration of memory cells connected to the adjacent word line may occur. Since deteriorated memory cells may result in failed programming operations, reliability of a flash memory device can be degraded.